The long-term objective of this research is to increase our understanding of the processes underlying memory storage. The proposed research is based on evidence that retention is altered by a variety of treatments if the treatments are administered shortly after training. Recent findings suggest that posttraining treatments may affect retention through influences on peripheral hormonal systems involved in the modulation of memory storage processes. The experiments are based on our findings that, in rats, the effects of posttraining electrical stimulation of the amygdala on retention are altered by adrenal demedullation and that the effects of peripherally administered epinephrine on retention are altered by blocking outputs from the amygdala. The research will investigate further the effects of peripheral hormones on memory and the involvement of the amygdala in the effect of peripheral hormones and other treatments affecting memory. The studies will investigate 1) the effects of epinephrine on retention of appetitively motivated learning tasks, 2) the effects of other stress-related hormones (ACTH, vasopressin) on retention in rats with stria terminalis lesions, 3) the involvement of release of epinephrine in the effects of posttraining treatments affecting retention 4) the involvement of the amygdala in the effects, on retention, of posttraining treatments affecting retention, 5) the effect, on retention, of adrenal demedullation combined with brain lesions (stria terminalis or locus coeruleus), 6) the effects of other peripheral hormones (ACTH) on retention in demedullated rats. These findings should increase our understanding of the physiological processes involved in memory, and thus have implications for understanding disorders of memory.